| Acronym | Definition |
|---|
| HACA | Human Anti-Chimeric Antibody (medicine) |
| HACA | Historical Armed Combat Association (now known as ARMA) |
| HACA | Hypothermia After Cardiac Arrest |
| HACA | human anti-chimeric antibodies |
| HACA | Haute Autorité de la Communication Audiovisuelle |
| HACA | Henderson Allied Community Advocates (Nevada) |
| HACA | Housing Authority of the City of Austin (Texas) |
| HACA | Homestead and Agricultural Credit |
| HACA | Homestead and Agricultural Credit Aid (Minnesota) |
| HACA | Housing Authority of the City of Annapolis (Maryland) |
| HACA | Hellenic Association of Communications Agencies (Greece) |
| HACA | Housing Authority of the City of Asheville (North Carolina) |
| HACA | Housing Authority of the County of Alameda (California) |
| HACA | Hydrogen-Abstraction/Carbon-Addition |
| HACA | Hemophilia Association of the Capital Area |
| HACA | Houston Air Cargo Association (Texas) |
| HACA | 6-Hydroxy-2-Aminocaproic Acid |
| HACA | Housing and Community Affairs (Texas) |
| HACA | Hawaiian Acres Community Association |
| HACA | Hyderabad Agricultural Co-Operative Association Ltd |
| HACA | Hmong American Community Association |
| HACA | Housing Authority of the City of Atlanta (Georgia) |
| HACA | Haitian American Community Association (Chicago, IL) |
| HACA | Hungarian American Cultural Association |
| HACA | Hamilton and Area Curling Association |
| HACA | Houston Area Council of ABWA |
| HACA | Headford and Corrib Anglers Association (Ireland) |
| HACA | Highway Advertising Control Act of 1971 |
| HACA | Highbury Area Community Association |
| HACA | Hoosick Area Church Association (New York) |
| HACA | Holocaust Assets Commission Act of 1998 |
| HACA | Hawthorne Airport Community Association (California) |
| HACA | H-bonding Acceptor Changed Area |
| HACA | Humboldt Academy for Career Advancement |
| HACA | Houston Area Carriage Association |
| HACA | Humanitarian Aid Corridor Act of 1996 |
| HACA | Hydrogen Acceptor Charged surface Area |
| HACA | Homebuilders Association of Central Arizona |
| HACA | Hearing Aid Compatibility Act of 1988 |
| HACA | Hammered Aluminum Collectors Association |
| HACA | Hampton Area Clergy Association (New Hampshire) |
| HACA | H-Abstraction Acetylene Addition (chemistry) |